Cornwall Council admitted that one of its offices “lit up like a Christmas tree” during an energy crisis was an accident last week. However, it’s not the first time that residents of Bodmin have spotted the Chy Trevail building illuminated after hours.

A dog walker discovered a fully lit-up but empty Chy Trevail at 9.30 on a Saturday night earlier this month. The building usually accommodates over 600 staff during office hours. The man, who took photos of the building on Beacon Technology Park with lights and screens left on, said: “I was out dog walking at Chy Trevail in Bodmin and I noticed the place lit up like a Christmas tree. How can the council justify leaving all the lights and TVs on?

“We’re constantly told there is an energy crisis. They put our council tax up. For what reason? Because they have forgotten to employ staff that are qualified to use a light switch?”

Cornwall Council has pledged to reduce its carbon impact to zero by 2030, with one of its key targets being the reduction of energy use and emissions in its buildings. A council spokesperson said: “Following an investigation, we can confirm the atrium lights at Chy Trevail were left switched on accidentally on this occasion. Training will be given to ensure this is an isolated incident.

“Cornwall Council is committed to reducing its energy use, and has taken many steps to do so, including the installation of solar panels at both County Hall in Truro and at Chy Trevail. A new lighting control system has also been installed in Truro to ensure the amount of time lights are left switched on is minimised.”

However, this is not the first time such an incident has happened in recent years. The council was accused of wasting energy five years ago when another dog walker, Nigel Bundock, took images of Chy Trevail lit up throughout the night. He also claimed the windows were left open when the heating system was on.

He described the discovery as “frustrating” and “annoying”, adding: “I was taking loads of photos to prove that that’s every day, it’s not just one-offs. Some will say I’m petty, but no, I work hard, I have to work every day to pay for that and the council tax.”

Cornwall Council blamed the out-of-hours illumination on an issue with the building’s lighting sensors, which it was working to repair.

Just last summer, Cornwall Council’s main office building – Lys Kernow (New County Hall) in Truro – was also photographed with all the lights on at gone midnight, which the council said was due to maintenance work. Residents compared the building to Blackpool illuminations.

Chy Trevail, which was build in 2015, has “a highly energy efficient design driven by a challenging DEC rating and incorporates 200kw photovoltaics to generate on-site renewable energy, low energy LED lighting, improved insulation, air-tightness and measures to reduce water consumption”.